Automatic phonograph tripping mechanism



Dec. 20, 1960 P. A. DE BOER AUTOMATIC PHONOGRAPH TRIPPING MECHANISMFiled July 23, 1957 v INVENTOR PETR S ANTONIUS DE 8051 ATTORNEYAUTOMATIC PHONOGRAPH TRIPPING MECHANISM Petrus A. De Boer, 60Godelindeweg, Naarden, Netherlands Filed July 23, 1957, Ser. No. 673,735

2 Claims. (Cl. 274-15) The invention relates to a phonograph with cammechanism for the automatic control of the pick-up arm, said mechanismbeing set rotating stepwise between the playing of two records by a pawlrod, which receives a reciprocating movement from the spindle of theturn-table and acts on a ratchet wheel connected with the cam mechanism.

A phonograph of this type is known from the U.S. Patent No. 2,620,194.

According to the invention this device is constructed in such a way:that after a number of rotational steps of the ratchet wheel the pawlrod is engaged and seized by the ratchet wheel; that at the end of thesubsequent rotational step the ratchet wheel receives a pre-rotation,which terminates the action of the spindle of the turn-table on the pawlrod; and that upon the needle entering the terminal groove of the recordbeing played the engagement of the pawl rod by the ratchet wheel iseliminated.

By this means the advantage is gained that the driving motor of thephonograph is not loaded, during the playing of the record, by thereciprocating movement of the pawl rod and, consequently, need notperform work to bring about this movement. Objectionable interferingnoises, which may be caused by the moving parts during the playing ofthe record, are thus avoided; the motor may be made smaller and wear isminimized.

The invention is to be elucidated more in detail with reference to thedrawing, which shows a diagrammatic plan view of an embodiment.

Fig. 1 shows only the essential parts of the device according to theinvention.

Fig. 2 shows the same parts, and in addition an embodiment of a devicefor eliminating the engagement of the pawl rod by the ratchet wheel uponthe needle entering the terminal groove of the record played.

The reference number 1 designates the spindle of the turntable. Fittedeccentrically on this spindle is a disc 2. The disc 2 co-operates with alever 3, which is adapted to pivot about a stationary axis 4. Connectedwith the free end of the lever 3 and adapted to pivot about it is a pawlrod 5. The righthand end of the pawl rod 5 has been shaped like a hook 6and co-operates with a ratchet wheel 7 of a cam mechanism (not shown)for the automatic control of the pick-up arm during the changing of arecord; said cam mechanism has not been shown in the drawing because itdoes not form part of the invention.

The toothing of the ratchet wheel 7 has been constructed locally at 8 insuch a way that the pawl rod 5 can be engaged and seized by the ratchetwheel 7.

The pawl rod 5 is acted upon by a tension spring 9, which tends to holdthe lever 3 against the disc 2 and the pawl rod 5 against the ratchetwheel 7.

The reference number 10 designates a member which, when moved in thedirection of the pawl rod 5, eliminates the engagement of the pawl rod 5with the ratchet wheel 7.

Fitted on the upper surface of the ratchet wheel 7 is a non-circulardisc with a cam 13. Against the rim of ate 2,965,377 Patented Dec. 1960the non-circular disc 15 presses, under the influence of a spring 16,the end of an arm 14, which is adapted to pivot about a stationary pivot17.

The device according to the invention is shown in the position in whichit is when a record is being played on the phonograph. In this positionthe ratchet wheel 7 is stationary The free end of the arm 1-4 restsagainst the flank of the cam 13. Owing to this the ratchet wheel 7cannot rotate in clockwise direction. The hook 6 rests in the engagingrecess 8. In consequence the position of the pawl rod 5 is such that thedisc 2 during its continual rotation cannot come into contact with thelever 3. The pawl rod 5 therefore is stationary.

When at the end of the record played the needle of the pick-up armenters the terminal groove of said record, then in a manner to beexplained more in detail the member 10 is briefly pressed against thepawl rod 5. In consequence the hook 6 is lifted from the engaging recess8. The pawl rod 5 is then pulled to the right by the spring 9, and thelever 3comes to rest against the disc 2. During the next revolution ofthe disc 2 the pawl rod moves to the right until the hook 6 engagesbehind the next tooth 11 of the ratchet wheel 7. During the subsequentregular reciprocating movement of the pawl rod 5 under the influence ofthe disc 2 the ratchet wheel 7 is rotated stepwise in the direction ofthe arrow 12. Through this stepwise rotation the automatic control ofthe pick-up arm during the changing of the record is brought about.

After some time the recess 8 arrives to the right of the place where inFig. l the reference number 11 has been placed. During the subsequentmovement to the right of the pawl rod 5 the hook 6 is engaged and seizedby the recess 8. If the pawl rod 5 then moves to the left again, theposition reached is approximately the one i1- lustrated in 1. Thisposition is not reached to the full, since the movement to the leftofthe pawl rod 5, conditionedby the disc2, is not sufficient for thispurpose.

At the end of thismovement the cam 13 is rotating gets clear of the arm14. The end of thearm 14 consequently comes to rest on the flank of thecam, as a result of which, under the influence of the spring 16, a smallfurther rotation in the direction of the arrow 12 is imparted to theratchet wheel 7. This rotation is such that the position of Fig. 1 isnow reached again.

The small further rotation results in that the pawl rod 5 is displacedslightly to the left by the righthand flank of the recess 8. Thisdisplacement puts the lever 3 out of reach of the disc 2. In this way itis ensured that the pawl rod 5 performs no reciprocating movement duringthe playing of a record. The motor of the phonograph accordingly neednot perform any work to bring about this movement, and the wear of theparts involved in this movement is minimized.

Fig. 2 will now be discussed. From this it appears how it can be ensuredthat upon the needle entering the terminal groove of the record beingplayed, the member 10 is briefly pressed against the pawl rod 5. In sofar as the same parts of Fig. 1 appear in Fig. 2, they have been giventhe same reference numbers.

The member 10 forms part of a lever 18, adapted to pivot about astationary axis 19. The lefthand end 20 of the lever 18 is bevelled andlies in the path of travel of a pin 21, which follows the rotation ofthe spindle 1 of the turn-table. When the pin 21 comes into contact withthe end 24), the lever 18 is slightly rotated in counterclockwisedirection about the spindle 19.

The reference number 22 designates the pick-up arm; this is shown indotted lines because it lies above the level of the other parts. Thereference number 23 designates the spindle of the pick-up arm. Securedto the spindle 23 is an arm 24; the latter accordingly follows themovements of the pick-up arm.

A plate 26 is adapted to rotate with friction about a spindle 25supported by the arm 24. This plate 26 rests against the righthand partof the lever 18.

When during the playing of a record the pick-up arm 22 gradually comescloser to the spindle 1 of the turntable, the arm 24 and, owing to thefriction between said arm and the plate 26, also the plate 26 is carriedalong. With every revolution of the turn-table the left hand end 20 ofthe lever 18 will be moved a short distance in the direction of thespindle 1. Upon the pin 21 passing along the bevelled portion of the end20, however, said end is each time pushed back again the same distance.The average position of the lever 18 will thus remain the same.

However, when the needle enters the terminal groove of the record beingplayed, the pick-up arm will suddenly receive a greater displacement.This displacement is also transmitted to the lever 18 by the plate 26,and ensures that the lefthand end 20 of the latter is engaged by the pin21 and that the lever 18 reaches the position shown in dotted lines, andwith its righthand end 10 eliminates the engagement of the pawl rod 5with the ratchet wheel 7. Shortly afterwards the pawl rod 5, under thecombined influences of the spring 9 and the disc 2, moves to the right.During this movement the member 10 is pressed back by an appropriatelyshaped projection 27 on the pawl rod 5, so that the hook 6 can engagethe next tooth of the ratchet wheel 7.

When the pick-up arm 22 sways outwards after a record has been played,the plate 26 comes into contact with a stationary pin 28, as a result ofwhich, while overcoming the friction between said plate and the arm 24,it is put in the right position for the playing of the next record.

The device described for operating the member 10, in which a servomechanism is employed, only serves as an example. The member 10 can alsobe caused to be controlled direct by the pick-up arm, or the pawl rod 5can be disengaged from the ratchet wheel 7 by means of the lever 24, ina modified form thereof.

The invention naturally is not confined to the feature that the pawl rod5 exercises a pulling action on the .vided.

What I claim is:

1. In a record player, a shaft adapted to control a pick-up arm controlcam, a ratchet wheel on said shaft, said ratchet wheel having a recesstherein, a turntable spindle having a disc thereon, a pawl rodengageable with said ratchet wheel and operatively connected with thesaid disc to cause rotation of said ratchet wheel upon rotation of saidspindle, means to operatively disconnect said pawl rod from said discconsequent on said pawl rod engaging with the recess of said ratchetwheel comprising a noncircular disc on said shaft having a steepshoulder and a spring-urged lever engageable with said shoulder of saidnoncircular disc, said shoulder, when engaged by said spring-urgedlever, adapted to yield to the force of said spring-urged lever to causerotation of said noncircular disc, said shaft, and said ratchet wheel todisconnect said pawl rod from said spindle, and means operable uponentry of the needle in the terminal groove of a record on the turntableto disengage said pawl rod from said recess.

2. A record player according to claim 1 wherein said means to disengagesaid pawl rod from said recess comprises a pivoted lever one end ofwhich is engageable with the pawl rod; an arm which follows themovements of the pick-up arm, a plate frictionally mounted on said armwhereby upon the needle of said pick-up arm entering into the terminalgroove of the record, said plate moves said end of the pivoted leveragainst said pawl rod, thereby disengaging said pawl rod from saidrecess.

References Cited in the file of this patent UNITED STATES PATENTS2,436,529 Pressley Feb. 24, 1948 2,747,879 Bacher May 29, 1956 2,803,465Dobrogowski et al. Aug. 20, 1957

